The present invention relates to devices for continuous monitoring power delivery from a source to provide an alert that there has been a power outage. More particularly, the present invention relates to power outage devices that are adaptable to a common power outlet, which provide an alert when there has been one or more power outages and, further, which provide information on the outage, e.g., the number of outages and the date, time, and duration of each outage, and the like.
There has been a long standing need for sophisticated power outage indicators for home use that are versatile, can be manufactured at low cost, and that are easy to install, operate, and maintain. For individuals who travel or are away from home for extended periods of time, it is important for them to know whether, in their absence, power has been interrupted so that these individuals can prepare for, e.g., food spoilage, clocks that display an incorrect time, and the like.
More specifically, there is a need for a reusable power outage indicator that provides a visual display and/or an audible alarm and provides memory storage for a plurality of power outage events. However, devices for detecting power outages for home and business use are known to the art.
For example, U.S. Pat. No. 4,479,118 to Cole, Jr. teaches a power outage indicator for use in locations that are not readily accessible. The power outage indicator of Cole, Jr. uses a liquid crystal display (LCD) cell to provide visual indication that power has been interrupted. More specifically, the LCD cell includes a pair of parallel electrodes between which is located a liquid crystal material. In manufacture, the cell is initially heated and an electric field is provided between the electrodes. As the cell is allowed to cool, the electric field causes the molecules of the liquid crystal material to assume first a homeotropic nematic orientation before the LCD cell reaches a smectic state. When the LCD cell is in a smectic state, the liquid crystal molecules align homeotropically, producing a clear exterior surface.
The Cole, Jr. power outage indicator also includes a current storing capacitor that is connected in series through a switch to the pair of electrodes. The capacitor is in parallel with the source. As long as current flows from the source, the switch is closed. However, when a power outage interrupts the flow of current, the switch is opened and current stored in the capacitor is delivered to the pair of electrodes. The flow of current past the pair of electrodes produces heat, which heats the liquid crystal material above its clearing point temperature. As the current and heat dissipate, the heated liquid crystal material cools. During this cooling process there is no electric field to align the homeotropic layers. As a result, cooling produces a different optical condition.
Problems with the Cole, Jr. power outage indicator include the complexity of the indicator, a lack of memory, e.g., number, time, and duration of the outage, and an involved resetting process.
U.S. Pat. No. 4,466,074 to Jindrick, et al. teaches a power outage timer that can be used in conjunction with a xe2x80x9csmartxe2x80x9d electronic watt-hour meter to record the duration of a power outage for the purpose of resetting the real-time value stored in the memory of the electronic watt-hour meter. The electronic watt-hour meter includes a microprocessor, a real-time value memory, and a clock signal source.
According to the Jindrick patent, if there is a power outage, an outage timer causes a timing capacitor to discharge. After the outage is over, the time it takes to recharge the timing capacitor is measured. The microprocessor converts the capacitor recharge time to a power outage time using look-up tables and a driver program. The microprocessor then adds the power outage time to the real-time value to correct the time to account for the duration of the power outage.
Accordingly, there is a need for a reusable power outage indicator that is easy to use, install, and operate; that provides a visual display and audible alarm of any power outage events; and that provides memory storage for a plurality of power outage events to provide the date, time and duration of each power outage event.
In one embodiment, the present invention provides a power outage detection device for alerting users of the number, time, and duration of one or more power outages, the device comprising:
a voltage input receiver for receiving voltage from a power source;
a voltage monitor for monitoring a reference voltage that is received from the power source;
a change in voltage detector for detecting a change in the reference voltage, wherein the change is determined by comparing the reference voltage with a threshold voltage and the change is of sufficient duration to constitute a power outage;
a microprocessor having a central processing unit;
a programmable real-time clock that is in communication with the microprocessor to provide current date and time data;
one or more input/output devices for communicating data to and from the microprocessor, wherein the one or more input/output devices comprises at least one of:
a signal that is in communication with the microprocessor to indicate that there has been one or more power outages;
a display that is in communication with the microprocessor to display data on demand; and
an auxiliary energy power supply that provides power to the device during the one or more power outages until the reference voltage exceeds the threshold voltage;
wherein the microprocessor comprises a plurality of memory that includes read only memory for storing one or more microprocessor driver programs and random access memory for storing power outage data for one or more power outages.